Rewrite approximate_row_count to SQL instead of PLpgSQL and remove
superfluous JOINs against pg_namespace. Adjust tuple calculation
for PG14 since in PG14 reltuples for partitioned tables is the sum
of it's children so we need to exclude those from calculation to
not doublecount.
Fix a number of issues with size and stats functions:
* Return `0` size instead of `NULL` in several functions when
hypertables have no chunks (e.g., `hypertable_size`,
`hypertable_detailed_size`).
* Return `NULL` when functions are called on non-hypertables instead
of simply failing with generic error `query returned no rows`.
* Include size of "root" hypertable, which can have non-zero size
indexes and other objects even if the root table holds no data.
* Make `hypertable_detailed_size` include one additional row for
storage size of objects on the access node. While the access node
stores no data, the empty hypertable may still take up some disk
space.
* Improve test coverage for all size utility functions. In particular,
add tests on regular tables as well as empty and compressed
hypertables.
* Several size utility functions that were defined as `PL/pgSQL`
functions have been converted to simple `SQL` functions since they
ran only a single SQL query.
The `dist_util` test is moved to the solo test group because,
otherwise, it gives different size output when run in parallel vs. in
isolation.
Fixes#2871
This change renames function to approximate_row_count() and adds
support for regular tables. Return a row count estimate for a
table instead of a table list.
A bug in the SQL for getting the size of chunks would use the
TOAST size of the main/dummy table as the toast size for the
chunks rather than each chunks' own toast size.
Getting an approximate row count for a hypertable involves getting
estimates for all of its chunks rather than just looking up a
single value in the catalog tables. This PR provides a convenience
function for doing the JOINs/summing.
The hypertable, chunk, and index size functions are
now split into main function and a corresponding ´pretty´
function. In chunk_relation_size_pretty() the ranges are
now converted into a human readable form when they are time types.
